My question is if we have an incoming signal coming from a usrp, How do
First, calibration is outside the scope (so to speak) of GNU Radio and
USRPs, so absolute measurements are going to require test equipment.
But, you can determine SNR and the peak amplitude above the noise floor
for some simple signals by viewing them on uhd_fft or a similar program.
Peak hold and averaging functions may get you close to what you want.
Fortunately, after a while, you won’t be new to GNU Radio any more.
I calculate the SNR, Peak Amplitude of the signal and the noise floor.
This first questions seem to be rather of a DSP nature than specific to
GNU Radio – for example, SNR only makes sense when you define what your
signal is. There is not “physical” quantity that describes SNR in a
piece of spectrum, it all depends on what you want to receive. You’ll
need to define a signal model, and mathematically quantify what SNR is,
and then build a flowgraph that calculates it.
using FFT block in companion how do I extract the frequency samples
and Power level for every sample.
The output of the FFT block is the FFT of the input vectors; I think
this is what you refer to with frequency samples.
Power level, again, is depending on how you define signal power, but
it’s common in signal to use the $L^2$ norm of a signal, and thus, the
square root of the sum of squares over a period of time.